1. Field of the Invention
The technical field of the present invention relates to a semiconductor device including a content addressable memory.
2. Description of the Related Art
The content addressable memory (CAM) is a memory that can determine whether data that matches for a set of data called data word is stored in the memory.
For example, the CAM determines if there is a match for a data word such as “10110”.
As the CAM, a binary CAM (BCAM), a ternary CAM (TCAM), and the like can be given.
In the BCAM, either of two values, “Low (0)” or “High (1)”, is stored in each memory cell.
In the TCAM, any one of three values, “Low (0)”, “High (1)”, or “X (Don't Care)”, is stored in each memory cell of a memory circuit.
Note that “X (Don't Care)” is a value which will match any input value in reading operation.
As an example of the CAM, a CAM including a capacitor disclosed in Patent Document 1 can be given.